Microwave Resonator for Single-Side Battery Coating Measurement
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Solution Overview
Problem
Existing methods for measuring the thickness and electrical conductivity of electrode coatings in lithium-ion batteries are time-consuming, destructive, and limited to small areas, lacking an effective online, non-destructive solution for double-side coated electrodes.
Innovation Solution
A sensor system combining a high-frequency microwave resonator, mid-frequency coil, and optional optical displacement sensor for contactless, single-side thickness measurements, using electromagnetic fields to probe surface impedance and dielectric properties, and infer porosity through basis weight measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical or electron microscope measurement is used, then thickness measurement precision is improved, but the measurement process becomes time-consuming and destructive
Solution Approach 1:
The patent replaces mechanical/optical measurement systems with electromagnetic sensing. The microwave resonator and eddy current sensor use electromagnetic fields to measure thickness without physical contact, eliminating the time-consuming sample preparation and mounting required by optical/electron microscopes while maintaining measurement precision.
Solution Approach 2:
The patent introduces electromagnetic fields as an intermediary between the sensor and the electrode coating. The microwave resonator and eddy current sensor detect changes in electromagnetic properties (resonant frequency, quality factor, impedance) caused by the coating thickness, providing rapid non-destructive measurements without direct physical contact.
2Measurement precision
If optical or electron microscope measurement is used, then thickness measurement precision is improved, but the measurement becomes destructive
Solution Approach 1:
The patent replaces mechanical/optical measurement systems with electromagnetic sensing. The microwave resonator and eddy current sensor use electromagnetic fields to measure thickness without physical contact, eliminating the destructive cutting and mounting required by optical/electron microscopes while maintaining measurement precision.
Solution Approach 2:
The patent introduces electromagnetic fields as an intermediary between the sensor and the electrode coating. The microwave resonator and eddy current sensor detect changes in electromagnetic properties (resonant frequency, quality factor, impedance) caused by the coating thickness, providing rapid non-destructive measurements without direct physical contact.
3Measurement precision
If conventional thickness measurement is used, then coating thickness can be measured, but it is limited to small areas and cannot measure single side of double-side coated electrodes
Solution Approach 1:
The patent segments the measurement function into two independent sensors: a microwave resonator for measuring one side of the electrode and an eddy current sensor for measuring the other side. This segmentation allows each sensor to be optimized for its specific measurement task and enables independent measurement of each coating side without measuring the total thickness first.
Solution Approach 2:
The patent creates a universal measurement system that can handle both single-side and double-side coated electrodes. The microwave resonator measures the first coating, and the eddy current sensor measures the second coating, allowing the system to adapt to different electrode configurations and measurement requirements.
4Productivity
If online measurement is implemented, then productivity is improved, but device complexity increases
Solution Approach 1:
The patent segments the online measurement system into two independent sensor modules: a microwave resonator module and an eddy current sensor module. Each module can be independently calibrated, maintained, and replaced, reducing the complexity of the overall system while enabling continuous online measurement of both coating sides.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables rapid, non-destructive, and continuous measurement of electrode coating thickness and conductivity, facilitating real-time defect detection and manufacturing process optimization.
Implementation Method 1
a high-frequency microwave resonator... The high frequency measurement is designed to probe the surface impedance and dielectric properties of the coating
Implementation Method 2
a mid-frequency coil... the conductivity measurements of the electrode coating are used as inputs to calculations involving the lower frequency coil to determine the thickness of the coating
Implementation Method 3
an optical displacement sensor... An optical displacement sensor measures the lift-off (separation between the measurement subject and the sensor) in real time
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
Sensor system for contactless, single-side thickness measurements of lithium-ion battery electrode coating includes a high-frequency microwave resonator, a mid-frequency RF resonator, and an optional optical displacement sensor. The high frequency measurement probes the surface impedance and the dielectric properties of the sample which are then used as inputs to calculations involving the lower frequency coil to determine the thickness of the coating. The optical displacement sensor measures the lift-off (separation between the measurement subject and the sensor) in real time and the data is used when interpreting the raw data obtained from the sensor system. The microwave resonator has a concave metallic mirror that is positioned above the electrode. An RF/microwave choke can be included in the microwave resonator to suppress radiative energy loss. The microwave resonator can be operated with one or more modes. The microwave resonator and RF resonator can be coupled to respective read-out circuits.